Installing Plywood Floors | Home Guides | SF GateAttaching the Panels. The builder applies a 1/2-inch bead of subfloor adhesive to the center of each joist before positioning the plywood panel. decking screws, spaced 6 inches apart on the seams and 8 inches apart on the face of the plywood, hold the panel in place. A screw gun is the quickest and most efficient way to insert the decking screws. The adhesive helps hold the panel, and it adds a bit of cushion between the joist and the plywood to reduce floor squeaks.